1. Field of the Invention
The present invention relates to a handheld device, and more particularly to a handheld device with switchable signal receiving modes.
2. Related Art
With the rapid technological progress and vigorous competition, business trip is rapidly becoming common. In addition, people have taken mobile phones along with them even on a tour in holidays. However, generally, conventional mobile phones are merely adapted to one frequency. Considering users having several phone numbers, the current mobile phone is configured with a dual module that can be inserted with two SIM cards, and is further equipped with a composite antenna therein. Thus, when different phone numbers are used, a telecommunication signal of an appropriate frequency corresponding to a certain phone number can be transmitted and received via the composite antenna.
Moreover, in order to enhance the functions of the mobile phone, some mobile phones are equipped with a global positioning system (GPS) or a network TV module, so that the users can perform the satellite positioning operation or enjoy network TV.
However, the prior art has some difficulties that are difficult to overcome.
Firstly, a mobile phone user may go abroad in a certain business trip, but a transmission frequency of the mobile phone is generally a fixed single frequency, and at the best circumstance, the mobile phone is equipped with a composite antenna to use together with a dual module. Unfortunately, the mobile phone may not meet the requirements of the frequencies of the telecommunication signals adopted by a local telecommunication system, i.e., the mobile phone cannot work. Even when the user has got a local telecommunication phone number, the user still needs a mobile phone conforming to the local telecommunication system.
Secondly, although some mobile phones are equipped with the GPS, such mobile phones still need to be equipped with an additional dedicated antenna for transmitting and receiving satellite signals, which further occupies some space within the mobile phone.
Thirdly, a mobile phone user may be a subscriber of the satellite TV, and the mobile phone generally transfers TV images over the telecommunication network. However, due to the different frequencies of the transferred signals, the telecommunication network cannot be combined with the satellite system, so an additional antenna for receiving satellite signals needs to be configured. Actually, considering the cost and phone volume, most manufacturers do not provide a mobile phone with satellite TV, which restricts the functions of the mobile phone.